I think it would be viable if you had a quick function that could turn a brushstroke into a shape. Or possibly if there was a setting to do the same thing automatically.

If there was a toggle where you could stroke the brush and then it would affect the shape and hit the toggle when you're done. And allow Xara to add or subtract nodes of these shapes based on this toggle.

Then you would have a seriously cool application.

Because if you can control/create shapes as you would doing a painting and be able to control the hardness or softness of edges, why would you then need a painting program?

Xara is still geared more towards a hobbyist designer than a professional illustrator/painter.

The ability to paint relies on the speed with which you can create and design your shapes. Creating organic shapes has never been Xara's strength.